I have read the other posts relating to this error message.
I have also tried the miriad of possible solutions - no success
I have also been attempting to use the following:
1. USBtiny to upload - following the tutorial on the Adafruit site. This has only added to the confusion.
The tutorial states the the USBtiny does not use the Com ports but uses USB. However when you try to compile a sketch - guess what!
The IDE asks why you haven't selected a com port via the 'tools' menu.
Is my UNO fried? I built a standalone as an exercise. The sketch installed on this was a simple blinking LED. The chip was programmed using my UNO and works fine.
I transferred the chip from the standalone, plugged into the UNO and lol! Pin 13 was blinking as programmed..
So the board is OK ?
I decided then to reload the same program, blinking pin 13, no surprises here that damned error is still present.
As a previous contributor remarked - this error is popping up all over the place. It's not something out of the blue after all the board is reporting it, it is not unknown.
So, why has there been no response from the developers. They must know about the problem and what specifically causes it, for sure they have formally recognised it.
I would dare to say that most users of Arduinos in whatever form will be non-professional so the developers should not be using them to come up with a solution to this problem.
I think I will just have to fork out for another board otherwise all projects will be ditched and I'm not prepared to do that.